Balanced automatic valve



Wd@ ik 13.936, E. RMA/50N BALANGED AUTOMATIC VALVE Filed Jan. 9, 1934 2 Sheets-Sheet l INVENTOR EMA/l//[L RAM/50N.

VENT BY j/ ATTORNEY Patented Feb. 4, 1936 UNITED STATES PATENT OFFIQE BALANCED AUTOMATIC VALVE Application January 9, 1934, Serial No. 705,841

2 Claims.

My invention relates to the art of preheating ,feed water for boilers and aims to provide a novel and reliable arrangement for such purpose.

It is common practice to provide locomotive engines with feed water heaters utilizing exhaust steam from the driving engine of the locomotive to preheat water being fed to the locomotive boiler. However, the locomotive driver often operates the feed pump of the locomotive when the driving engine is not in operation, and it is therefore desirable to provide means for supplying live steam to the feed water heater when the driving engine is not operating. Such means have been, moreover, proposed. One such proposed arrangement was placed in a line branched from the steam line of the pump for the feed water heater and the steam space of such heater, such line containing a partially balanced valve adapted to open by the pressure of the fluid whose fiow was controlled thereby and normally Aheld closed by the pressure of the steam in the main steam pipe of the locomotive at a point near the engine. The steam pressure at such point drops, of course, when the throttle valve is partially or entirely closed. Such an arrangement is attractive in that it is simple and inexpensive. Diiiiculties have been encountered, however, in adapting it to practical use. Such diniculties have originated chiefly in the fact that the pressure in the steam to the feed pump varies thru quite a range during the operation of the engine due to the fact that the feed pump is run at different speeds at different times. It follows that the steam pressure at the pump is throttled down to various different pressures at different times. The resulting variations in pressure in the pump line have caused the partially balanced valve to open to pass live steam to the feed water heater at widely different pressures in the steam pipe of the engine so that the partially balanced valve, instead of opening at the desired steam pressure in such pipe, will open too readily to admit the live steam to the feed water heater, or will not open readily enough, depending upon whether the pump operating pressure is more or less throttled.

It is an object of my invention to provide an arrangement of the general type described above and which shall be free from the difculties outlined.

In order that my invention, together with its objects and advantages may be fully and readily understood, I will now describe in detail by way of illustration and in connection with the accompanying drawings a feed water heater arrangement for locomotives in accordance with my invention. In the drawings,

Fig. l is an elevational View of a locomotive having an exhaust steam feed waterl heater arrangement in accordance with my invention.

Fig. 2 is a vertical sectional view taken through the center of the balanced valve for the live steam supply shown in Fig. l.

In the arrangement illustrated in the drawings, lll is the boiler of a locomotive having feed pump l2 and a feed Water heater I4 connected to receive water from such pump. Exhaust steam from the exhaust nozzle I6 of the locomotive is normally furnished to the interior of the feed water heater I4 by a conduit !8 whenever the cylinders 2t of the driving engine of the locomotive are in operation. Live steam from the turret 22 of the locomotive may be furnished to the interior of the casing of feed water heater Ill through pipe 24 whenever pump l2 is in operation provided the throttle valve 28 of pump l2 in the pipe line 24 is open. As is evident, whenever the throttle valve 28 of the pump l2 is closed, the live steam is cut ofic from the casing of valve 26, no heat being required in the heater I4 at such times. The internal construction of the valve 26 is best understood from Fig. 2. 'Ihe valve 26 comprises a casing ill enclosing a movable valve member 32 adapted to cooperate with a flat seat 34 to permit or cut off ow of steam through the casing 3G in the direction of the arrows 36, 36. Member 32 is formed at one end, the upper end as shown, to act as a piston 32a whose face is subject to the pressure in a chamber 38, which is in one end of casing St. chamber 38 is connected by a pipe @El with the interior of the main steam pipe 4l of the locomotive so that the face of the member 32 is exposed to the pressure of the steam flowing to the engine cylinders 2B in a manner tending to force member 32 into contact with seat 3&1 to cut off now of live steam to the heater. Part 32a is proportioned so that there is noflow so long as the main throttle valve is open enough to provide the required amount of exhaust heating Steam to the heater Hl. At its end opposite piston 32a, member 32 has a part 32h for balancing the inlet pressure on 32a and which is guided in a chamber 42, such chamber being connected to the atmosphere, or other zone of low pressure, as indicated by the Word vent, As shown, chamber 42 is in the lower end of casing 30 and, preferably, pipe 4 connects into the lower end of chamber 42 to carry away any condensate which may work down into such chamber. A

The

spring 46 is placed in the chamber 42 and arranged to bear against the bottom of such chamber at one end and against the portion 32b at its other end. Spring 46 thereby tends to throw member 32 out of contact with seat 34 so as to permit flow of live steam to heater I4. Valve 26 is so constructed as to be completely balanced; that is, entirely unresponsive to changes in pressure in pipe 24 which conducts fluid to the inlet side of the valve. To insure such manner of action, guide portion 32h of valve 26 has a diameter equal to that of the center line of the ring seat 34. Of course, when valve member 32 has lifted from seat 34 there is some unbalanced pressure tending to keep the valve open. Such action, however, is advantageous in preventing chattering or member 32. Spring 46 is properly chosen so as to throw valve member 32 away from seat 34 to permit flow through the valve at a given desired pressure of steam in pipe 4| less than the full operating pressure for the engine. In the installation illustrated, it is assumed that such action will occur when the pressure in pipe 46 and chamber 33 has been reduced to 100 pounds gauge, the heating effect of the exhaust steam from the engine under such conditions being insuicient to raise the feed water to the temperature desired.

It will be observed that member 32 is made in two parts, the upper or piston part 32a being connected to the lower guide portion 32h by through bolt 48. Such design of the valve member 32 permits its assembly in the casing 3). Piston portion 32a being of larger diameter than the passage through the seat 34, must be inserted from one side of the seat, and portion 32h, also being larger than the opening through the seat 34 must be inserted into the casing 30 from the other side of the seat. I provide therefore two caps which thread into casing 36 in alignment with the axis of member 32. Above piston portion 32a is a cap 50 having a threaded skirt 5| thereon which projects into the casing 30 and surrounds the chamber 38, forming a guide for the upper portion of part 32a. At the lower end of casing 3|! is a second cap 52 having a threaded skirt 53 thereon which projects into the casing 30 forming a socket for the lower end of the spring 46. The parts 32a and 32h therefore can be readily inserted into casing 30 when caps 50 and 52 are not in place and then connected by the thru bolt 46; after which, spring 48 is inserted and the caps are screwed into casing 30 as shown in the drawings. It will be seen that bolt 48 extends thru the plane of seat 34 and thru the centre of the opening thru such seat.

I have found that the satisfactory operation of a steam heated feed water heater designed to use exhaust when placed on live steam depends greatly on predetermining the amount of live steam delivered to such heater. If there is no restriction to steam flow in line 24, or other like line for supplying live steam, there will often be a waste of steam thru the exhaust nozzle into the stack of the locomotive. Also the feed water may be heated to a higher temperature than necessary, thereby also wasting steam. If, however, it is attempted to limit the rate of steam flow to some predetermined amount by a xed choke, difliculties are encountered in that a given choke, no matter how well it may be designed for given conditions, is incapable of adjustment to different conditions in use. I have accordingly provided valve 26 with means whereby the maximum steam flow therethru for given conditions may be not only determined exactly, but may be changed readily to meet another set of conditions. The means shown for such purpose comprises an adjustable screw threaded into the cap 50 in alinement with the bolt 48 and adapted to be set to limit the opening movement of member 32 by contacting with one end of bolt 46. When screw 54 has been set as desired, it may be fixed as long as desired in such adjusted position by a jam nut 56. Preferably nut 56 is in the form of a cap so that screw 54 is concealed and tampering with the adjustment of screw 54 by unauthorized persons is thereby minimized.

Of course, the effect of spring 46 can be adjusted when desired by putting shims in the joint 53a between cap 52 and the lower end of casing 33. However, I do not limit myself to any particular way of adjusting the spring 46 as several ways of adjusting springs in valves are well known in the art.

I claim as my invention:

1. In a locomotive having a boiler, a feed water heater normally supplied with exhaust steam from the locomotive engine, a pump connected to feed water to said boiler through said heater, piping between said boiler and said pump for supplying live steam to the latter, a valve in said piping controlling the pressure of steam therein for regulating the rate of operation of .l

said pump, and a connection between said piping and heater for supplying live steam to said heater during operation of said pump; a valve member in said connection balanced to be unaffected by the pressure of live steam in said connection; a piston connected with said valve member and subject to the engine operating pressure for normally maintaining said valve member in closed position; and spring means acting on said valve member in opposition to said engine operating pressure for moving it to open position at a definite engine operating pressure irrespective of the pressure of live steam supplied to said pump and heater through said piping and connection under the control of said valve.

2. In a locomotive having a boiler, a feed water heater normally supplied with exhaust steam from the locomotive engine, a pump connected to feed water to said boiler through said heater, piping between said boiler and said pump for supplying live steam to the latter, a valve in said piping controlling the pressure of steam therein for regulating the rate of operation of said pump, and a connection between said piping and heater for supplying live steam to said heater during operation of said pump; a valve member in said connection balanced to be unaffected by the pressure of live steam in said connection; a piston connected with said valve member and subject to the engine operating pressure for normally maintaining said valve member in closed position; spring means acting on said valve member in opposition to said engine operating pressure for moving it to open position at a definite engine operating pressure irrespective of the pressure of live steam supplied to said pump and heater through said piping and connection under the control of said valve; and adjustable means for limiting the opening movement of said valve member to regulate the amount of live steam supplied to said heater through said connection.

EMANUEL RAWSON. 

